Traction members for footwear are generally known. The soles of footwear containing traction members usually contain a plurality of ground-engaging or gripping portions or members which may be permanent or may be removable and replaceable. The ground contacting portion of the traction members have been single or multiple spikes or various arrangements of protrusions within a single traction member. The ground contacting portion is often made of metal, rubber, polymer, or other material suited for the intended use. To retain the traction members containing these ground contacting portions within the soles of footwear, it is generally known to screw studs of light metal or synthetic polymer into threaded bores formed in the soles.
Although screw threaded traction devices are the most common, they are not without problems. The threads on the studs of traction members can become stripped and lose their attachment capabilities. Further, over-tightening of the stud may reduce the ability of the stud to be retained in the shoe. Also, removing threaded traction devices from threaded bores can be extremely time consuming. In addition, a threaded traction device screwed into a threaded bore can become partially unthreaded during a rotation of the footwear relative to the ground, and, when partially unthreaded, clumps of soil may become caught between the traction device and the sole of the footwear which can cause an imbalance in the wearer. If the traction device becomes unscrewed, the wearer may be unaware of the problem until the traction device falls off or until a large clump of soil stuck between the sole and traction device gains the attention of the wearer. Once the problem is identified, the wearer must interrupt play to find the traction device or a replacement device and to re-rotate the traction device and tighten it adequately within the bore. Furthermore, even with the growing popularity of "soft" spiked shoes, a special tool is still required for the installation and removal of the spikes. Thus, if the tool becomes misplaced, it can create problems for the wearer if a traction device needs removal or tightening.
The prior art discloses some efforts to solve the problems of screw threaded attachments, or to just devise a replacement for screw threaded attachments. Most of the prior art, however, would require a wearer to buy footwear fitted with soles having specially designed bores which could only fit accordingly specially designed traction devices. That is, a wearer would have to buy into a "system" of footwear and traction devices. Unless the system is hugely commercially successful, replacement traction devices would probably have to be specially ordered, which is inconvenient. Such a system could end up being quite costly since the wearer would have to buy new shoes and order replacement parts.
Thus, there is a need for traction devices which can be placed in screw threaded bores, found in most footwear which accommodate removable traction devices. There is a further need for such traction devices to be placed in screw threaded bores by using a method other than rotating. There is also a need for traction devices which can self insert upon application of pressure from the wearer's foot upon the ground. A further need exists for traction devices which can be easily removed when desired, but which do not compromise the attraction of the traction device within the bore in the sole. There is further a need for a traction device which meets the above-described needs and is, in addition, inexpensive to manufacture. There is further a need for a traction device having a shaft system which meets the above-described needs and which can utilize a head having any ground engaging means desired, such as a metal spike or polymer protrusions.